Multiple-lobe antenna assembly



April 27, 1954 P, 1 ALLEN 2,677,055

I l MULTIPLE-LBE ANTENNA ASSEMBLY Filed Oct. 6, 1949 I lui-l a 11 f j l PHILIP. J. ALLEN i,

ATTORNEY Patented Apr. 27, 1954 2,6779655 MULTIPLE* ANTENNA, SQSEMBLY ennui-1nr Auen; Washingwu,A D.. o. AQBWQD Qillllllfl 494.59%?! 0- 1,192982.'

vlclaims.- (o1. 2me-sass) v seigle, element.. ieee not Substantially. @freetime s., atieabityeeethe,deeds/llt aies Ottllepattenls Still another olaeetis t@ pr'vldefeur sectoral lnventioni relates to.: antenna; eetl more particularly to. milltplerlebe-z antenna as: sembl'es.-

Prior systems? for olctainingA ingiationsg of thel posiztion-f0f a reetine surface@ Qt-energ 4 meiatiye; 0f the ing 'surface'. on energy, source. pps yy spect to.v equal-1y spaced; axes; ef d the antennasa The escanear; @fv the lndleell is; partially determine1:15pm1 the separation between thelaxesof.directinityfand i th are-mounted ilnhe. CIQSQS llyl permitted. by their stru saly charia er The prior systems: A 2 AAfor@ailing which operate in response toV transmit* employ a aan. directional usually lar to the antennas of the group, functionin a transmitting or areceivirlgA elemena necessarily symmetrically.v po sit',;ioned` with respect to the antermas' 0fv the; group. The` lresult11sst l-lll'fu.ffl l5.; 'Jr-llil lllaiclflle Cel Wilhnot Onlybulkfy' and: rlrfidllfes` eleetswhieh tene, eeen? lvntloni to decrease tracking efliciency, butalso increases 25 Fig. 2 s a fnontveywoffthe aritiura'assernloly' separation between the equally spaecl aiesfofl Qi Fig. 1 ,B1}` l directivity by an amOllrll? at; least e nal to the Eig. 3f is.a,pe 1 "speptive. View, partly in section, dimensions of the sith antenna elanL t Qi a eer-tienei elle canelle assembly illustrated Itis therefore an objectief the-present; inveri-- ine-Fig. 1 1. tion t0 provide a^I10Ve1f multiple-1Gb? @melilla 30 Wtrll'reflffn?? IRQ@ Paftlllllly @figs 1 and assembly free from the foregoing disagiyantages. 2 of th ciravyings, anatriterinav A" ssembly con:

Another object is t'oproyide a novel n iulti-A le- Strute I1 aGCOTdnG-'Wth th DYICDlSOf'tll lobe antennal assembly hav-ing; a pluralityo equallyl spaced axes of drlectilitl Wjh; minimum separation therebeinyeell, and, an axis of qirecf 3; tivity symmetrically positioned thereof,

Another object is to provide. a noyel antennaassembly providing. a plurality of symnjietjriic al directional lobe patterns with minimum separatiii'i nnetniwithn ings eleclQeelle ele/09131.69., o Vennen: It isieanressly understqpe hqwever. that tic,ation` only agie not ais'a'fde'rinitin of 'the omits 'lf er ectiye. View of a multiple-lobe four 'eiet'romagnetie sectoral: horns mg, l, rg and e'ij 'in juxtaposie e .a thereof. tffrm a unitary streelde@ llavine e front, afee @Chiel te" the' 'ceelleneflfmoull arflsef sectoral' hemel tion between the directivityI axes; thereof', and:y a 4 0v Each of the sectoral no ns inc es a pair cf single'directional' lobe. patternzhaving an? axis( Ofi' 319,1?? RQS, l5, 2l D f-l'l'l'l'fllled A 3. DIODS directivity equally spaced fromr the, axes ofy cii- [6., end a tl'iroat vsection-il'. Thefare portions rectivity. "G hg hogjg inthe' Still another object. of the presentinvention r tliec'as'eofelecis tol provider amultipleJ-lobe antenna assembly 4 5 tric pl horns, andwhen `Ina"ne`tic plane horns comprisingV a plurality of symmetrieallyr i alge e @perm VVs, aref increase@ p @stioneddeepromagneti: 119x115 establish in-a d1 ion perpendicular toL the electric Vector..

plurality of symmetrical lobe patterns minimum .separation between the a s elv directivity thereon. and asingle-- ant Sitioned .centrally- Qf.- the, ner

direc: for thetypof liorn'sfernployedf coupled to they respectivel 'tliratf' sefcij. ,ns"J I 'T a conventional "veilen @reprises an. ,leer symmetrically present"'iiivjerit'ionl isgfdisemseii tpeieinirieiqomg 3 llfconstructec ofniet'al'li'c mater l'. horns' ment 1go- 59 |8`,' [9, :2U and 2 1, operating at the proper Vinode 3 spaced directional lobe patterns with absolute minimum separation between the directivity axes thereof.

As mentioned heretofore, it is an object of the present invention to provide an antenna assembly having a plurality of symmetrical directional lobe patterns with minimum separation between the directivity axes thereof, with novel means for producing a single directional lobe pattern symmetrically positioned with respect to the plurality of patterns without substantially effecting the separation between the directivity axes thereof.

The foregoing means comprises a rod-type dielectric directional antenna element 22, constructed of polystyrene, or any other suitable dielectric material, positioned centrally of the sectoral horns with its longitudinal axis, or its axis of directivity, lying symmetrical with respect to the directivity axes of the horns. The juxtapositioned ilare portions l5 and uniiared side portions l5 are uniformly cut away about the center of the unitary structure throughout the length thereof to provide space for a metallic tubular member 23 supporting the dielectric antenna element 22. The metallic tubular member 23 is secured to the cut edges of the nare portions I5 and the unared side portions i6, and extends from a plane spaced from the mouth sections l4, through the unitary structure in symmetrical relation with the axes of directivity, and terminates in coupling relation with a rectangular wave guide 24.

Fig. 3 of the drawing discloses the structural relationship between the metallic tubular member 23 and the wave guide 24, and the energy coupling means between the dielectric antenna element 22 and the wave guide 24. As shown, the end of the wave guide 24 adjacent the plane of the throat sections I1 is closed by a metallic plate 25 having a centrally located circular opening if therein coextensive with the internal diameter of the tubular member 23, and the dielectric antenna element 22 extends throughout the length of the tubular member 23 and terminates in the plane of the wall 25 with a cylindrical portion 26, of reduced diameter, projecting into the wave guide 24. The length and diameter of the portion 26 is selected to provide proper impedance matching at the operating frequency. It is expressly understood that adequate coupling may be provided between the dielectric antenna element 22 and the wave guide 24 by terminating the radiating element 22 within the wave guide 24 perpendicular to the wall 25, or by other means well known to the art.

.As shown particularly in Fig. 2, the metallic tubular member 23 is positioned centrally of the sectoral horns within the flare portions i5 and without the throat sections l1. This feature of the invention, in addition to the fact that the tubular member 23, with the dielectric antenna element 22, occupies a relatively small portion of the total projected area of the flare portions l5, provides a multiple-lobe antenna assembly wherein the centrally positioned antenna element 22 has substantially no effect upon directivity characteristics or attenuation. Moreover, any change in directivity or attenuation eects all horns equally, and therefore the optimum comparative, directivity characteristic obtained by joining the horns in symmetrical juxtarelationship is noteffected thereby. I

It is expressly understood tl1ai3,ll 1A v,antenna assembly may be constructed in any*c onyenientA manner, for example, by building up four sectoral horns from the centrally located tubular member instead of joining four horns as described heretofore, that a plurality of electric plane horns, magnetic plane horns, compound horns or conical horns derived from circular wave guides, may be formed or juxtapositioned in symmetrical relation, and that the centrally positioned antenna element may comprise other shapes of dielectric material, such as rectangular for example, as well as other types of end-fired elements. Moreover, the sectoral horns may be employed to receive electromagnetic energy with the rod 22 functioning as a radiating element, or vice versa, and the assembly may be employed as a feed to illuminate a reector or lens, or as a terminal antenna element.

There is thus provided by the present invention a novel multiple-lobe antenna assembly for providing a plurality of symmetrical directional lobe patterns having minimum separation between the axes of directivity thereof, and a single directional lobe pattern positioned symmetrically of the patterns without effecting the separation between the axes of directivity or the characteristics of the lobe patterns, and without substantially increasing energy attenuation. Multiple-lobe antenna assemblies constructed in accordance with the principles of the present invention are inherently less bulky than systems provided heretofore and are more readily adapted for use with precision tracking mechanisms.

Although only one embodiment of the present invention has been disclosed and described herein it is expressly understood that various changes and substitutions may be made therein without departing from the spirit of the invention as well understood by those skilled in the art. Reference therefore will be had to the appended claims for a definition of the limits of the invention.

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

What is claimed is:

1. A multiple-lobe antenna assembly comprising a plurality of antenna elements each providing a directional lobe pattern, separate wave guides connected to each of said antenna elements, means mounting said antenna elements relative to each other to establish minimum separation between the axes of directivity of each of said patterns, a single antenna element providing a single directional lobe pattern, and mounting means supporting said single antenna element on said plurality of antenna elements with the single directional lobe pattern thereof symmetrically positioned with respect to the directional lobe patterns of said plurality of antenna elements and -still another vwave guide connected to said single antenna element.

2. An antenna assembly comprising a plurality of electromagnetic horns joined together to form a unitary structure having a frontal area substantially equal to the combined mouth areas of said horns, and an end-fired antenna element mounted centrally of said structure.

3. An antenna structure comprising a plurality of electromagnetic horns each having a flare portion and a mouth section, means symmetrically mounting said horns in contact at. said mouth sections vto form a unitary structure having fa plurality of axes of directivity' equally-distant from the center thereof, each of said horns having a corresponding portion thereof adjacent the center of said structure removed to denne an opening lying longitudinally of said horns within the flare portions thereof, separate wave guides connected to each of said horns, an antenna element positioned in said opening, and still another wave guide connected to said antenna element.

4. An antenna assembly comprising a metallic tube terminating a wave guide'and supporting a dielectric antenna element, and four electromagnetic horns mounted in quadrature about said tube with each quadrant of said tube comprising a portion of the nare of one of said horns, and separate wave guides connected to each of said horns.

5. An antenna assembly comprising four electromagnetic horns joined together` in quadrature relationship at the mouth sections thereof with symmetrical axes of directivity, separate wave guides connected to each of said horns, a tubular member positioned centrally of said horns and extending into said horns symmetrically of said axes within the are portions thereof, and a dielectric antenna element carried by said tubular member, and still another wave guide connected to said antenna element.

6. A microwave antenna assembly comprising a plurality of similar electromagnetic horns each having flare portions and mouth sections, separate Wave guides conected to each of said horns, means joining said horns in juxtaposition at said mouth sections, and a rod-type dielectric antenna element having a diameter less than twice the small dimension of the projection of any one of said are portions to the plane of said mouth sections positioned centrally of said horns, and still another wave guide connected to said antenna element.

7. A microwave antenna assembly comprising a plurality of electromagnetic horns each having flare portions and mouth and throat sections, separate Wave guides connected to each of said horns, means joining said horns in juxtaposition at said mouth sections, and an end-red antenna element positioned centrally of said horns and extending longitudinally through said horns within the flare portions and without the throat sections thereof, and still another wave guide connected to said antenna element.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,398,095 Katzin Apr. 9, 1946 2,415,807 Barrow Feb. 18, 1947 2,425,336 Mueller Aug. 12, 1947 2,437,281 Tawney Mar. 9, 1948 2,458,885 Warren Jan. 11, 1949 2,460,401 Southworth Feb. 1, 1949 2,473,446 Riblet June 14, 1949 2,480,829 Barrow Sept. 6, 1949 2,487,759 Kircher Nov. 8, 1949 2,530,079 Riblet Nov. 14, 1950 2,540,839 Southworth Feb. 6, 1951 

